Inhibin and p27 interact to regulate gonadal tumorigenesis

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Published on: August 4, 2019

S C Cipriano1, L Chen, K H Burns

  • 1Department of Pathology, Baylor College of Medicine,One Baylor Plaza, Houston, TX 77030, USA.

Molecular Endocrinology (Baltimore, Md.)
|May 29, 2001
PubMed

Insights

Absence of tumor suppressors inhibin and p27 accelerates ovarian and testicular cancer development in mice. Double mutant mice lacking both inhibin and p27 exhibited earlier tumor onset and increased mortality compared to single mutants.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • Tumor suppressors are critical for preventing uncontrolled cell proliferation and cancer.
  • Defects in tumor suppressor genes like p27 (a cyclin-dependent kinase inhibitor) and inhibins (TGF-beta superfamily members) are linked to various cancers, including gonadal tumors.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying gonadal tumor formation in the absence of inhibins.
  • To determine if p27 and inhibin exhibit additive tumor suppressor activity in the gonads.

Main Methods:

  • Analysis of cell cycle protein regulation in gonadal tumors from inhibin alpha knockout mice (Inha(-/-)) using Northern blot and immunohistochemistry.
  • Generation and analysis of double mutant mice lacking both p27 and inhibin alpha (p27(-/-)Inha(-/-)).

Main Results:

  • Inha(-/-) mice showed elevated cyclin-dependent kinase 4 (Cdk4) and cyclin D2 mRNA, with decreased p27 protein in gonadal tumors, suggesting dysregulated cell cycle progression.
  • Double mutant p27(-/-)Inha(-/-) mice exhibited significantly earlier onset of ovarian and testicular tumors and increased mortality compared to Inha(-/-) mice.
  • Tumor foci were observed as early as 2-4 weeks in double mutants, with 100% mortality by 8-10 weeks.

Conclusions:

  • Increased Cdk4/cyclin D2 activity and decreased p27 activity contribute to gonadal tumor formation.
  • p27 and inhibin demonstrate additive tumor suppressor effects in the gonads.
  • Combined absence of p27 and inhibin accelerates tumor development and lethality in mice.

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